102 ROBERT M. YERKES 



of all, to pull the food toward him, thus indicating a natural 

 tendency which is important in connection with the statements 

 just made. Subsequently he learned that the banana must be 

 pushed through and obtained at the farther end of the box. 

 I am not prepared to accept the solution of this problem as 

 satisfactory evidence of ideation, but I do know that few ob- 

 servers could have watched the behavior of the orang utan with- 

 out being convinced that he was acting ideationally. 



Draiv-in Experiment 



An interesting contrast with the box and pole test is fur- 

 nisl\ed by what may be called the draw-in experiment. This 

 was planned as a simple test of Julius's ability to use a stick 

 to draw things into his cage from beyond the wire side. A 

 board was placed, as is shown in figure 34 of plate VI, with 

 sides to hold a banana, carrot, or some other bit of food, in 

 position. In the actual test either a carrot or a banana was 

 placed about two feet from the wire netting and a stick two 

 feet long was then put into the cage with the ape. 



When this situation was first presented to Julius, he looked 

 at the banana, reached for it, and failing, picked up a bag from 

 the floor of the cage and tried to push it through the wire mesh 

 toward the banana. He also used a bit of wire in the same 

 way, but was unable thus to get the food. As soon as a stick 

 was placed in his cage, he grasped it and used it in a very defi- 

 nite, although unskillful, way to pull the banana toward him. 

 He was extremely eager and impatient, but nevertheless per- 

 sistent in his efforts, and within five minutes from the beginning 

 of the first trial, he had succeeded in getting two pieces of 

 banana, using always his left hand to manipulate the stick. 

 This test was repeated a number of times with similar results. 

 He had from the first the ability to use a stick in this way, and 

 the only difficulty with the test as a means of obtaining evidence 

 of ideational behavior is that the possibility of imitation of 

 man cannot be certainly excluded. 



Lock and Key Test 



By my assistant it was reported on May 5 that the orang 

 utan had been seen to place a splinter of wood in a padlock 

 which was used on the cages and to work with it persistently. 



